While most of the candidates for the London mayoralty have cast various shades of doubt over the wisdom of building more roads in the capital, the Silvertown Tunnel has taken another step forward.

The Transport for London board has cleared the way for an official approach to central Government for permission to proceed with the project.

TfL will submit a Development Consent Order – the means for obtaining the go-ahead for “nationally significant infrastructure projects” – and has confirmed that work could begin as early as 2018 and be fully operational by 2022/23. The timetable is built on the Secretary of State giving approval by the summer of 2017.

The Silvertown Tunnel will work as a companion to the congested Blackwall Tunnel. Both will be tolled to control the level of traffic with the new tunnel allowing for the growth of cross-Thames bus services.

More than 4,000 people responded to a public consultation by Transport for London on the plans, which ran for eight weeks at the end of last year. Some 58% of respondents supported the construction of the tunnel and 31% opposed, with air pollution a major concern.

Graphic showing the proposed location of Silvertown Tunnel

The London Chamber of Commerce welcome the milestone move. It said: “Building Silvertown Tunnel is essential to relieve delays and provide an alternative route when problems occur. It will help to keep traffic moving in a growing area of London, giving businesses access to new markets and suppliers, and giving people in east London better access to jobs.

“London Chamber has long campaigned for additional river crossings in the east of the capital. Targeted investment is essential to service a rapidly expanding population in the East in order to relieve congestion and improve traffic flow.”

The No To Silvertown Tunnel protest group is urging people to lobby the mayoral candidates, saying it’s not too late to halt the project.

Campaigners said: “The timetable isn’t set in stone. And the new mayor can change all this by scrapping the scheme as soon as he or she is elected. So May’s City Hall elections are vitally important.”

Road tunnel plans

Meanwhile, the current mayor has underscored his commitment to road building, announcing new measures to ease congestion by 20%.

Boris Johnson has suggested that small tunnels and “flyunders” could unlock land for houses but the eye-catching centrepiece of his strategy are two major east-west tunnels funded by Vehicle Excise Duty – if devolved to the capital – and tolls.

The first tunnel, known as the Northern Cross City Corridor, would run from the A40 at Park Royal to the A12 at Hackney Wick in the east. A second tunnel could run from the A4 in Chiswick to the A13 in Beckton, near the Royal Docks .

Mr Johnson said: “Around eight of every 10 journeys in London are made using our roads which is why it is vital that we think big. We must deliver long-term solutions that will not just make the most of the space we have for road users, but bring environmental and amenity improvements to local areas.

“By pushing forward strategic initiatives we are outlining today, we will lay the foundation for the next wave of improvements to everyone’s experience of the road network across the city.”

TfL’s managing director of planning Richard de Cani said: “We need to take a different long term approach to how we use London’s road space, to manage capacity and better utilise valuable land for housing and creating public spaces. The planning we do today will benefit Londoners for generations to come.”